As the dimensions of features of semiconductor devices continue to be reduced, lithographic techniques and tools may need to be modified to accurately form functioning integrated circuit devices. Reticle masks may need to be modified from their intended design in order to avoid issues associated with forming features on a wafer that are smaller than the wavelength of photolithographic light being used to form those features, such as light diffraction and constructive or destructive interference of light. In some cases, new lithographic techniques, such as double-patterning, may help in overcoming some limitations of older techniques, but often pose new problems and challenges. There is thus a continuing need for improved methods of lithography, and particularly for improved methods of double-patterning lithography.